Written by Adrian Pyrke
The bushfire situation in the Tasmanian Wilderness World Heritage Area (TWWHA) has worsened significantly in the last 40 years. In the early 1980s, malicious and spiteful lighting of fires was rampant, particularly along the Lyell Highway, although this human malevolence seems to have largely abated. Accidental ignitions from campfires and other human folly require vigilant controls, but they are not the most significant threat. Since the early 2000s fires started by dry lightning have become the most significant concern. A common pattern, apparently rare until the last 15 years, is a dry lightning thunderstorm followed by a day of very hot, dry and windy weather. In February 2007 dry lightning started several fires in southwest Tasmania that rapidly developed into huge conflagrations. One of these, the Reynolds Creek fire, travelled over 30 km in a day. Another large fire started on the same day and burnt to the top of the Western Arthurs. In January 2013, while the Dunalley fire was raging, the Giblin River fire in the southwest was started by lightning and burnt over 40,000 hectares under the worst bushfire weather that southern Tasmania has experienced for a long time.
The intensity and ferocity of these large lightning fires is hard to imagine – obvious from a distance because of the immense plume of smoke reaching many kilometres up into the atmosphere. Few people saw these fires closely as they were occurring, but observations made afterwards tell the sorry tale. The sheer scale of these fires is daunting and not fully appreciated by many Tasmanians. Organic soils, fauna, fire-sensitive rainforest and alpine vegetation suffered, but fortunately most of the vegetation burnt was the more fire-adapted buttongrass. These are not the kind of fires that we want to see in the TWWHA. Unfortunately, however, we should expect to see more.
Are lightning fires normal in southwest Tasmania?
Comments have been made on www.bushwalk.com about the efforts of the Parks and Wildlife Service to extinguish these ‘natural’ fires – some people believe they should be allowed to run their course. But how natural are these lightning fires? It is conceivable that climate change has altered the patterns of lightning storms and associated rain – indeed, scientists in the 1980s noted that lightning fire was largely absent from southwest Tasmania. It certainly isn’t now. The total mix of ignitions, regardless of source, is what fashions vegetation and associated biota; more important factors are the season of burning, size of fires and frequency. The actual source of the ignition, be it a match, a flare, a fire stick or a bolt of lightning, does not make it an inherently correct kind of fire in terms of maintaining natural diversity. There is definitely a place for appropriate fire, however, to maintain a healthy environment.
Inappropriate and appropriate burning in the wilderness
In the late 19th and early 20th century, white people destroyed large areas of our most fire-sensitive conifer forests and alpine heathlands in western Tasmania, by ignorant burning as well as by other activities such as mining. Aboriginal people burnt regularly for cultural reasons for thousands of years, yet King Billy pine and deciduous deech, both trees that take hundreds of years to recover following fire, co-existed in vast stands – many of these have gone in the last 150 years. The Indigenous burning must have been applied skilfully, specifically and judiciously, and the extensive areas of flammable buttongrass visible today are evidence of this active land management. The rainforest, conifers and alpine heathland we have left are very precious and no opportunity should be missed to accord fire protection to these fire-sensitive areas. It is likely that climate change will make this a significant challenge.
Effective fire management in remote wilderness
Effective fire management depends on a range of risk management actions, none of which, on their own, provides a complete solution. Putting out unwanted fires, or suppression as it is called by the professionals, is important and, while improved success in recent decades has been aided by the development of technology, equipment (e.g. helicopters) and commitment, fire-fighting can only do so much to protect the remote Tasmanian wilderness. The ability to quickly detect lightning and fires using technology (e.g. satellite imagery, aircraft and remote lightning detectors) has become an important weapon, but it hasn’t removed the problem. Fires in buttongrass can spread very quickly and some lightning fires attain an uncontrollable size so rapidly that early suppression is all but impossible. Moreover, on days such as 4 January 2013 when fires in Tasmania destroyed over 200 houses, the highest priority for all fire-fighters is protecting people’s lives, so the destructive impact of the fires in the wilderness is hard to address with the limited resources available in Tasmania.
Using fire to fight fire
Using fire to fight fire is another fire management option. Bushfire researchers have developed computer simulation models that are able to test how planned fires reduce the impact of the larger, more intense unplanned fires. One such study tested many different planned fire scenarios lit in buttongrass in southwest Tasmania. These models create fires that spread through realistic vegetation, over actual terrain and are based on real weather from meteorological records. Fortunately the fires are all in cyberspace so many ‘experiments’ can be designed and tested. The evidence from the simulations is that planned fires in buttongrass, applied at the right size and strategic locations, can significantly reduce the unwanted burning of alpine vegetation and rainforest in southwest Tasmania. This is because the planned fires become barriers across the landscape that limit the spread of the destructive summer fires.
Planned burning of buttongrass
The technical understanding of the right conditions under which to burn buttongrass is now well developed, based on research and practice over the past 25 years. Planned burning is conducted mostly in autumn when the rainforest and alpine vegetation is sodden wet but the buttongrass burns nicely under these conditions which are milder than in summer. Thus the risk of accidentally burning the areas that should be protected from fire is extremely low. The weakest link is the weather forecasting for remote areas; however, forecasting accuracy will continue to improve in leaps and bounds over the next decade as it has over the preceding ones. So fire as a management tool can continue to be skilfully applied in the right places in the TWWHA.
The complexities of controlled burning
One challenge is to further develop our understanding of how fire impacts buttongrass vegetation, although much knowledge has been acquired from research. While buttongrass is certainly much more tolerant of fire than rainforest or native conifers, how often can it be burnt and yet maintain its natural diversity? This is a complex question of spacing and timing of planned fires that also provide a quantifiable benefit for protecting the fire-sensitive vegetation. While the simulation modelling demonstrates the protection benefit, the model has weak components that require better data inputs to provide more reliable answers. For example, we currently have a poor understanding of how and when fire burns in Tasmanian rainforest – in an average year there are only a couple of days when the rainforests are dry enough and the wind is sufficient to carry the fire through the vegetation. Therefore rainforests rarely burn, but they can.
Ongoing research and active management are crucial
Planned burning on its own is not the total answer to protect the fire sensitive natural values of the TWWHA. Nor is fire suppression. The modelling evidence suggests, however, that a lot of planned fire is required to make a difference. Simply dabbling in tiny areas will not be enough. Planned fire needs to be applied, the impacts on flora, fauna and soils monitored, and models further refined when new or better data becomes available. A real, live experiment with planned fire requires implementation with judicious periodic review of its effectiveness and impacts. The risk is that, without this active management, the rainforests, conifers and alpine vegetation will continue to degrade and disappear and there is always the possibility of even larger and more catastrophic summer bushfires.
Managing the fire threat to the TWWHA requires a more resources, a lot more
Planned burning in the Tasmanian Wilderness World Heritage Area is afforded very limited resources at present and not nearly enough is being done. A focus on protecting people, properties and towns is understandable but fire management in the remoter parts of Tasmania should not be neglected – it is a big part of the responsibility of custodianship of the natural values. Furthermore, there is an opportunity for Aboriginal people to re-establish burning and cultural links to the country that they lived in and managed for thousands of years. While the patterns of burning from pre-European time are not well known and may not be easy to replicate, contemporary Aboriginal custodianship and management of natural values in the wilderness are entirely compatible.
Only a week after I wrote this article, western Tasmania was hit by an unprecedented number of lightning strikes that ignited in excess of 80 bushfires. At the time of writing this postscript, fires are still burning and many will continue to do so all summer. The worst impact on fire sensitive forests and alpine vegetation may still be to come. Dire predictions about climate change and fire threat to the TWWHA are unfortunately very real, as we can now see. The time for action and increased investment in planned burning and fire suppression is now.
A Second Postscript
Now at 28 April 2016, the lightning fires from 13 January are still smouldering in southwest Tasmania but fortunately will spread no further. The fire agencies will review their operational response, as they do routinely, and understand how to be better prepared for next time. Only with realistic quantification of the extra resources required (e.g. remote fire-fighters and helicopters) to protect the fire-sensitive values of wilderness areas, and therefore, of course, the cost to the public purse, can the political process move forward. Thinking bigger than the scale of what has been done in the past is required. We need a lot more.
Planned burning will not mitigate the risk to the fragile regions of the central plateau where, unlike the southwest, there are no extensive areas of less fire sensitive vegetation in which to conduct management burns. The only tool we have for the plateau is rapid fire suppression response. Increased access and new roads are not likely to reduce the bushfire risk either, remote fire-fighters need to get dropped right next to remote fires, not just a few kilometres closer. Unfortunately there may still be times when factors such as bad weather conspire against a rapid extinguishment, even with well-resourced fire-fighting teams and all the dedicated intent in the world.
About the author
Adrian Pyrke worked a total of 25 years for the Tasmanian Parks and Wildlife Service as a ranger, fire management officer and state fire manager, retiring in 2014. His service commenced in 1977 but included an interlude away from the Parks and Wildlife Service between 1982 and 1994 during which he studied, worked as a botanist in Victoria and completed a PhD in vegetation ecology. He is currently working as a fire consultant.